Communication systems (e.g., telephone communication systems) are integral in many applications. For example, industrial and military applications rely on communication systems for efficiency and safety. Many currently used communication systems are conventional copper telephone systems with heavy cables and strong sensitivity to electrical interference. Further, typical conventional communication systems require electrical power at each location in the communication chain. In the event of a power failure the usefulness of such systems may be limited. Back-up power sources (e.g., battery systems, uninterruptible power supplies, etc.) are sometimes used; however, the cost of installation and maintenance of such back-up power sources at a plurality of locations may be cost-prohibitive.
Thus, a need exists for, and it would be desirable to provide, improved bi-directional communication systems.